Extreme ultraviolet (EUV) light is used in applications such as extreme ultraviolet lithography (EUVL). The extreme ultraviolet (EUV) light may be generated using an EUV source in which a target material is irradiated by a laser source. The irradiation of the target material by a high power laser source leads to the generation of plasma which emits EUV light. A collector situated in a vessel focuses the photons of the plasma so that the photons are directed out of the vessel and into an EUV consuming system such as an extreme ultraviolet lithography system (EUVL).
To monitor the generation process, EUV sensors can be used to measure the energy of the EUV light. In vessels provided with multiple EUV sensors, significant EUV energy discrepancies have been observed between the multiple EUV sensors.
It is in this context that embodiments arise.